Hampster Problem!!!?

Ok, I just got a female teddy bear hampster today and the person who sold it to me from petsmart said she was very loving. So when i took skittels home (i named her skittles) i set up her new home. Then at least 2 hours later, i went to feed little skittels then when i stuck my hand in she jumped up on my hand and started to bight me and tear the skin of my hand like she was a devil hampster!!! Then i got her to fall off my hand then she stared at me like she was going to kill me and started hissing and running around like crazy!!!! I know some of you might say she is just scared but the manager from petsmart said she did not act like this to the other people she lived with!!! what should i do????